1. Field
Apparatuses and methods consistent with exemplary embodiments relate to a valve unit, a microfluidic device having the same and a method for driving the valve unit and, more particularly, to a valve unit for control of a micro fluid flow, a microfluidic device equipped with the same and a method of driving the valve unit for control of a fluid flow.
2. Description of the Related Art
A microfluidic device is utilized to conduct biological or chemical reactions by operating upon a small amount of fluid. The microfluidic device has a microfluidic structure provided in a platform in different forms or shapes such as a chip, a disk, etc.
The microfluidic structure typically has a chamber to receive a fluid therein, a channel through which the fluid passes or flows and a valve to control the fluid flow, wherein the chamber, channel and valve are combined and arranged according to different assembly designs.
In order to conduct various experiments including biochemical reactions on a chip, a microfluidic structure is arranged on a chip type platform what is referred to as a ‘bio-chip.’ Especially, a device fabricated for multi-stage treatment and/or operation on a single chip is referred to as a ‘lab-on-a chip’.
In order to flow and transport a fluid in a microfluidic structure of a microfluidic device, a driving pressure is generally required. The driving pressure may be capillary pressure or pressure generated using an alternative pump may be used. In recent years, a centrifugal microfluidic device having a microfluidic structure mounted on a disk type platform, capable of conducting a series of operations while shifting a fluid by centrifugal force has been proposed. The microfluidic device is often referred as a lab compact disk (CD) or a lab-on-a CD.
The valve of the microfluidic device may be operated in a magnetic control manner or using a phase transition material, so as to open and close a channel.
For use of a phase transition material, a normally open valve is operated by installing a chamber to receive the phase transition material close to a channel and heating the phase transition material to flow into the channel, in turn closing the channel.
However, a microfluidic device using centrifugal force to transport a fluid has a disadvantage in that a channel may not be completely closed using a phase transition material.
Some processes such as DNA extraction, induction of polymerase chain reaction, etc. are implemented at a relatively high temperature. A phase transition material generally has poor heat tolerance and entails a problem in that the phase transition material closing a channel is fused in a high temperature environment, in turn opening the channel even in the case where the channel must be closed.